Food preservation system

ABSTRACT

A system for storing food, including a plurality of food-containing packages disposed inside an endless high-density polyethylene wall for surrounding the plurality of food-containing packages and defining an airtight container. The high-density polyethylene wall is no less than one-quarter inch thick and is formed by engaging a heat source into thermal contact with container rim portion and a lid portion, energizing the heat source to partially melt both the rim portion and the lid portion, disengaging the heat source, and introducing the molten lid and rim portions into pressurized contact with one another to fuse them together to define the airtight container.

TECHNICAL FIELD

The novel technology relates generally to the field of food packaging, and, more particularly, to a method and system whereby food to be preserved is first freeze-dried and compressed, and then sealed in a low-oxygen environment in a glass container.

BACKGROUND

There are many reasons why storing food and other valuable items in a remote location for later consumption and/or use may be desirable. While there are many attractive long life storage containers and systems currently available, they all tend to be small and fragile. Thus, there remain needs for a storage system that can protect large volumes of food and other items for extended periods of times and under in adverse physical conditions. The present novel technology addresses these needs.

SUMMARY OF THE NOVEL TECHNOLOGY

The present novel technology relates to a method and system whereby food to be preserved for indefinitely long periods of time is first packaged or freeze-dried and then sealed in a low-oxygen/low-moisture environment in a high density polyethylene container. One object of the present novel technology is to provide an improved food preservation system. Related objects and advantages of the present novel technology will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of containers and sealing equipment according to a first embodiment of the present novel technology method for preserving food.

FIG. 2 is an enlarged perspective view of the heat source shown in FIG. 1.

FIG. 3 is an enlarged perspective view of a container and lid being prepressurized and/or heat treated according to the embodiment of FIG. 1.

FIG. 4 is an enlarged perspective view of the container and lid being fused under pressure after heat treatment according to the embodiment of FIG. 1.

FIG. 5 is an enlarged perspective view of a sealed container according to the embodiment of FIG. 1.

FIG. 6 is a schematic view of the method according to the embodiment of FIG. 1.

FIG. 7 is a time/pressure profile according to the embodiment of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the novel technology and presenting its currently understood best mode of operation, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the novel technology is thereby intended, with such alterations and further modifications in the illustrated device and such further applications of the principles of the novel technology as illustrated therein being contemplated as would normally occur to one skilled in the art to which the novel technology relates.

FIGS. 1-7 illustrate a first embodiment of the present novel technology, a system 10 for preserving the integrity of foodstuffs and other perishable materials, typically foods 12 that have been packaged for preservation, in some instances freeze-dried and in other instances compacted for long term storage. The system 10 may also include dried and compacted food masses that have been enveloped in a partial vacuum formed inside a plastic or glass packaging. More typically, the food mass 12 is wrapped in a protective sleeve, such as a plastic film or the like, prior to positioning within the packaging. Individual packages 18, such as presupplied Meals Ready to Eat (MREs) are placed into a container 20 that includes a central or canister portion 22 and a lid portion 24 sealedly connected thereto to define a substantially contiguous enclosure 20. The enclosure or container 20 is typically made of high-density polyethylene (HDPE), high molecular weight polyethelene (HMWP), or the like. The enclosure 20 is typically no less than about ¼ inch thick. The canister portion 22 has an upper rim portion 25 defining an opening at one end. The portions 22, 24 are typically sealed by butt-welding the lid portion 24 to the rim portion 25 under pressure, but may alternately be sealed by suitable fusion or sealing techniques, such as laser or torch fusion (wherein a laser, torch or like device is used to sufficiently heat the intersection of the lid and central portions 24, 22 such that they flow together to form, when cooled, a contiguous enclosure 20), by the application of adhesives, or the like. Typically, water absorbing agents or desiccants 26 are placed in the enclosure 20 to further assure a substantially anhydrous environment therein, and, more typically, oxygen getters 27 are likewise placed in the enclosure 20.

In operation, the sealing process 100 begins with one or more food packages 18 (which may more generally include any package or item that is desired to be protected) being placed into the canister or barrel portion 22. The canister or barrel portion 22 is typically cylindrical (more typically a unitary wall defining a cylinder having a bottom portion but no top lid portion), but may be of any convenient shape. More typically, the barrel portion 22 is between about eighteen and about forty-eight inches tall, still more typically between about thirty and about thirty-six inches tall, although the cylinder may be of other convenient dimensions. Next, a heat source, typically a double sided hot plate 105, is preheated to a desired temperature sufficient to soften the container and lid material and then positioned in snug thermal contact 110 with the lid portion 24 and the rim portion 25. The portions 24, 25 may be pressed 115 against the heat source 105 with moderate to high pressure. The heat source 105 is energized 120, the applied pressure is typically reduced 122, and the lid and rim portions 24, 25 are partially melted 125 to define molten lid and rim portions 130, 135. The heat source is typically controlled so as to not overheat the HDPE, HMWP or like material and thus degrade its structural integrity. The heat source 105 is then removed 140, and the molten lid and rim portions 130, 135 are introduced to one another under sufficiently high pressure 145 to fuse 150 the lid portion 130 to the rim portion 135 (and thus to the container portion 22) to define a sealed container system 10.

The hot plate 105 typically includes an electric heating element 160 positioned between a pair of thermally conducting disks 165 (typically, an anodized aluminum outer ring portion with an insulating ceramic center portion, such as perlite concrete or the like) connected in thermal communication therewith. The disks 165 more typically include an insulating nonstick layer 170, such as polytetrafluoroethylene (PTFE), on the surfaces opposite the heating element 160. The disks 165 assist in transferring sufficient heat directly to the portions 130, 135 to render them molten, without overheating the contents 18 of the container 20.

When desired, the system 10 may be accessed by breaking or removing the lid portion 24 from the canister portion 22, such as with a pruning saw or powered circular saw or the like, or otherwise penetrating the container 20. The contents 18 may then be removed and used.

EXAMPLE

One or more packages 18 are placed 200 into a one-quarter inch thick HDPE barrel 22 about thirty inches high and having a diameter of about twenty four inches. A quarter-inch thick HDPE lid portion 24 is provided, wherein the lid portion 24 has a diameter of about twenty-four inches. A double sided hot plate heat source 105 including an electric heating element 160 positioned between a pair of thermally conducting disks 165 is positioned in snug thermal contact 110 with the lid portion 24 and the rim portion 25 of the barrel 22. The portions 24, 25 are pressed 115 against the respective disks 165 under 950 PSI for about 1 minute. The pressure is decreased 122 to 450 PSI. The heat source 105 is energized 120 and preheated, and then engaged to heat the rim portion 25 and the lid portion 24 sufficiently to soften and partially melt 125 the lid and rim portions 24, 25 to define molten lid and rim portions 130, 135. This requires a heat soak of about 1 minute, forty-five seconds. The heat source 105 is then quickly removed 140 (taking a total of about 10 seconds) and the molten lid and rim portions 130, 135 are immediately introduced 215 to one another and pressed against one another under pressure ramped up to 950 PSI over a period of about thirty seconds 220 to fuse 150 the lid portion 130 to the rim portion 135 (and thus to the container portion 22) to define a sealed container system 10. It takes about 15-45 seconds, more typically about 30 seconds, to ramp the pressure up to 950, where the pressure remains applied for at least another two minutes and fifteen seconds, typically for about three more minutes. Once sealed, the system 10 is tested to withstand at least about 6 PSI pressure. The sealed container system 10 is typically stored for future use, such as warehoused or buried to a depth of at least about three to four feet (below the depth threshold wherein temperature is relatively constant year round to take advantage of a constant storage temperature of about fifty four degrees Fahrenheit), and, if desired, up to a depth of about thirty feet or more. The container system 10 is typically cylindrical to facilitate easy movement by rolling, and more typically features a corrugated outer surface to provide additional structural support.

While the novel technology has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It is understood that the embodiments have been shown and described in the foregoing specification in satisfaction of the best mode and enablement requirements. It is understood that one of ordinary skill in the art could readily make a nigh-infinite number of insubstantial changes and modifications to the above-described embodiments and that it would be impractical to attempt to describe all such embodiment variations in the present specification. Accordingly, it is understood that all changes and modifications that come within the spirit of the novel technology are desired to be protected. 

What is claimed is:
 1. A system for storing food, comprising: a plurality of food-containing packages; and an endless high-density polyethylene wall surrounding the plurality of food-containing packages and defining an airtight container; wherein the high-density polyethylene wall is no less than one-quarter inch thick.
 2. The system of claim 1 wherein the high-density polyethylene wall further comprises a barrel portion and a lid portion fused to the barrel portion.
 3. The system of claim 1 wherein the lid portion is laser-fused to the barrel portion.
 4. The system of claim 1 wherein the lid portion is butt-welded to the barrel portion.
 5. The system of claim 1 and further comprising a water absorbing agent and an oxygen getter positioned within the airtight container.
 6. The system of claim 1 wherein the airtight container may be buried to a depth of at least about thirty feet.
 7. A system for preserving food, comprising: a quantity of food; a high-density polymer wall surrounding the quantity of food and defining an airtight enclosure; and an anhydrous, low-oxygen atmosphere formed within the enclosure; wherein the high-density polymer wall is at least about ¼ inches thick; and wherein the airtight enclosure can withstand at least about 4 PSI.
 8. The system of claim 7 wherein the enclosure also includes oxygen getters and water absorbing agents positioned therein.
 9. The system of claim 7 wherein the quantity of food includes a plurality of packages of foodstuffs.
 10. The system of claim 7 wherein at least some of the quantity of food is freeze-dried.
 11. The system of claim 7 wherein at least some of the quantity of food is a plurality of prepackaged MRE's.
 12. A method for preserving food, comprising: a) placing at least one food package into a high density polymer canister, wherein the high density polymer canister has a rim portion defining through which the at least one food package is passed; b) engaging a heat source into thermal contact with rim portion; c) engaging a lid portion into thermal contact with the heat source; d) energizing the heat source to partially melt both the rim portion and the lid portion; e) disengaging the heat source from thermal contact with both the partially melted lid and rim portions; f) introducing the molten lid and rim portions into pressurized contact with one another; g) fusing the lid portion to the rim portion to define an airtight enclosure containing the at least one food package; wherein the lid portion is made from the same high density polymer as the high density polymer canister.
 13. The method of claim 12 wherein the airtight enclosure can withstand a pressure of at least about 6 PSI.
 14. The method of claim 12 wherein the high density polymer canister and lid portion are both at least about ¼ inches thick.
 15. The method of claim 12 and further comprising: h) before d), pressing the rim and lid portions against the heat source with a first pressure; i) during d), pressing the rim and lid portions against the heat source with a second pressure less than the first pressure; and j) during f), the lid and rim portions are fused together under a third pressure greater than the second pressure.
 16. The method of claim 15 wherein the first pressure is about 950 PSI; wherein the second pressure is about 450 PSI; wherein the third pressure is about 950 PSI; wherein h) lasts about 1 minute; wherein d) lasts about 1 minute and 45 seconds; wherein e) takes about 10 seconds; wherein f) occurs immediately after e); and wherein g) occurs immediately after f) and lasts about 3 minutes.
 17. The method of claim 12 and further including k) burying the airtight enclosure to a depth of at least about four feet. 